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Wiring diagrams

Looking for 1993 U240 coach wiring diagram.  Thanks 😊

Re: Wiring diagrams

Reply #1 –
Terry,

Welcome.

12 VDC or 120 VAC?

And, any particular area/device you are interested in?
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Wiring diagrams

Reply #2 –
12v
Coach
Source of power to dash incl start lock switch

Re: Wiring diagrams

Reply #3 –
Terry,

A good place to start your troubleshooting is the IGNITION SOLENOID.

Open the dash (hinged in front by windshield).

Ignition solenoid is in front of driver's area.

Two large lugs-- one should always have chassis battery voltage.  The other large lug should only have voltage (same voltage as the other large lug) when the ignition is on.

Let us know what you find.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Wiring diagrams

Reply #4 –
Quote from: TerryW –
Looking for 1993 U240 coach wiring diagram.
First 3 links below (from our excellent ForeForum Library) might be what you seek.  Last link is to the main Library page, where you will find many folders full of potentially useful info.

https://www.foreforums.com/index.php?action=media;sa=media;in=4746

https://www.foreforums.com/index.php?action=media;sa=media;in=3856

https://www.foreforums.com/index.php?action=media;sa=media;in=3857

https://www.foreforums.com/index.php?action=media;sa=album;in=165

1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Wiring diagrams

Reply #5 –
No juice to the hot side.  If I jump from alt post on isolator to start batt post I get juice.

Re: Wiring diagrams

Reply #6 –
What is battery voltage at chassis battery?  house battery?

Does the boost switch work?
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Wiring diagrams

Reply #7 –
12.7
14
Don't know

Re: Wiring diagrams

Reply #8 –
Quote from: TerryW –
No juice to the hot side.  If I jump from alt post on isolator to start batt post I get juice.
Engine running or engine off?  The center (alt) post on isolator should not be hot unless the engine is running.
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Wiring diagrams

Reply #9 –
Cant start engine without jumper.  I gotta trace some more cables.

Re: Wiring diagrams

Reply #10 –
Typical OEM 4-post isolator wiring connections:
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Wiring diagrams

Reply #11 –
Yeah, mine is 3 post aftermarket and now that I have rewired it the alt no longer charges

Re: Wiring diagrams

Reply #12 –
Where can I get a four post?

Re: Wiring diagrams

Reply #13 –
Better question...why four posts?]

Re: Wiring diagrams

Reply #14 –

The 4-post isolator fitted by the factory to older Foretravel coaches is a bit of a mystery.  Several ideas found on this Forum over the years about why...  Perhaps it was all they could get at the time - who knows?

You'll notice in the photo I posted that there is a jumper connecting the coach battery post to the "extra" 4th post on the isolator.  So the 4-post isolator still functions the same as a 3-post model.  It can be replaced with either a 3-post model or a 4-post model.  They should both work equally well.

The Victron ArgoFET 3-post 200A isolator is a excellent choice - suitable for use on any Foretravel coach.  It has virtually zero voltage loss between the alternator post and the battery posts, making it very efficient.

Amazon.com: Victron Energy Argofet Battery Isolators 200-2AC (2 Batteries...

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Wiring diagrams

Reply #15 –
A photo and description of the cables at the
Isolator would be helpful.
Any paper work with the isolator?
Did it ever work correctly?
Justin & Cathy Byrd
1995 U280 "Old Faithful"
36' Build #4673
C8.3 Cummins
Allison MD3060R 6 speed - retarder
Powertech 10KW  4cyl Kubota

Re: Wiring diagrams

Reply #16 –
No paperwork
Don't know.  New to me.

Don't know how to add  pic.

Center post from alt
1st post to coach batt
3rd post to engine batt and dash solenoid

Re: Wiring diagrams

Reply #17 –
Quote from: TerryW –
...mine is 3 post aftermarket and now that I have rewired it the alt no longer charges.
You need to get out your multimeter and do some basic charging system trouble shooting.  The first diagram I linked in Reply #4 shows how a 3-post isolator should be connected.  After you have the battery cables connected to the isolator, then you'll need the big engine running (whatever that takes).  With engine running, you can measure and record the voltage at the following points:
1.  B+ output terminal on the alternator
2.  ALT post on the isolator
3.  COACH battery post on isolator
4.  ENGINE battery post on isolator
5.  The POS (+) post on the COACH battery bank where cable from isolator is connected
6.  The POS (+) post on the ENGINE battery bank where cable from isolator is connected
7.  BOTH of the large terminals on the ignition solenoid (under the lift-up dash cover in front of driver seat)

Let us know the results of these readings.
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Wiring diagrams

Reply #18 –
Quote from: TerryW –
Don't know how to add  pic.
How to add a photo when you reply to a post:
1.  Take the photo, then transfer to your computer.
2.  Click on the "Reply" button below a post to compose your reply.
3.  Look down below the box where you type your reply for "Add files by dragging & dropping or selecting them"
4.  Click on the words "selecting them"
5.  In the page that opens, navigate to the photo file on your computer.
6.  Click on the desired photo file name.
7.  At bottom right corner of page click on "upload".
8.  If the photo uploads successfully, you should see a little tiny image icon appear in the "Add files..." box.
9.  Click on "Post" button to publish your reply.
10.  Note:  You will not actually see the full sized photo until your reply is posted in the thread.
1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Wiring diagrams

Reply #19 –
Thabk you all..

Cables are good.  Voltages are good...except no charging voltage to start batteries.  Will be testing isolater in a different way.

Re: Wiring diagrams

Reply #20 –
To test diode-based isolator with three lugs:

Center lug is from Alternator B+ and with engine off, 0 VDC.  With engine running (and around 1,100 RPM) in the high 14's.

One outer lug to chassis battery and will read chassis battery voltage with engine off.  With engine on it should read in the lower 14's.

Other outer lug to house  bank and will read house bank voltage with engine off.  With engine on, it should read in the low 14's.

Yes, if batteries are deeply discharged and alternator output is insufficient to achieve target voltage, that is also OK-- just need to recheck when batteries charge rate is within the alternator's capability.

Let us know what you find.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Wiring diagrams

Reply #21 –
Bats are fully chgd.

Need to test diodes

Re: Wiring diagrams

Reply #22 –
Quote from: TerryW –
Bats are fully chgd.

Need to test diodes

Then, my test immediately above should tell you what is going on.

Also a good idea to check the other/small wires/terminals on the alternator.  The sense wire is small-gauge and have seen some not connected, some wires broken.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Wiring diagrams

Reply #23 –
Thank you very much for helping me with this issue!

Internal reg.  No sensing wire.

Alt will chg if there is 12v available at output post.  There isn't preaumably because of the diode.
 

Re: Wiring diagrams

Reply #24 –
Very likely you have an incorrect alternator for a system with diode-based battery isolator. OE, and with a diode-based isolator, you need a DUVAC alternator.

There is about a .7 VDC drop across the diodes (turned into heat, which is why the aluminum fins to get rid of the heat).

If the alternator is putting out, say 13.5 VDC, the "far side" of the diodes and hence both batteries will only be charged at 13.5 minus .7= 12.7 VDC.

If not a DUVAC, you can either change the diode-based isolator or get the correct alternator.

Short term, you can move all the terminals in the diode-based isolator to one lug to get you where you are going.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020